Azure API SharedKeyLite in Powershell - powershell

Question

I'm trying to implement a SharedKeyLite Authorization header function in powershell. This is to connect to Azure Tables REST API. I'm missing something cause I keep getting an error:
Server failed to authenticate
the request. Make sure the value of Authorization header is formed correctly including the signature.
function GenerateHeader($accountName, $accountKey, $action)
{
$xmsdate = get-date
$xmsdate = $xmsdate.ToUniversalTime()
$xmsdate = $xmsdate.toString('r')
$newLine = "`n";
$message = $xmsdate + $newline + "/" + $accountname + "/" + $action;
$hmacsha = New-Object System.Security.Cryptography.HMACSHA256
$hmacsha.key = [Convert]::FromBase64String($accesskey)
$signature = $hmacsha.ComputeHash([Text.Encoding]::UTF8.GetBytes($message))
$signature = [Convert]::ToBase64String($signature)
$headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$headers.Add("x-ms-version", "2014-02-14")
$headers.Add("x-ms-date", $xmsdate)
$headers.Add("Authorization", "SharedKeyLite " + $accountName + ":" + $signature)
return $headers
}
UPDATE:
Here's code that calls this function. The $action variable is set to the URI string.
$uriString = "https://$StorageAccountName.table.core.windows.net/Tables"
$headers = GenerateHeader $StorageAccountName $StorageAccountKey "Tables"
Invoke-RestMethod -Uri $uriString -Method $method -Headers $headers -Body $body
And here's the error it throws.
Invoke-RestMethod : AuthenticationFailedServer failed to authenticate the request. Make sure
the value of Authorization header is formed correctly including the
signature. RequestId:4215377d-0002-0044-1a92-94cd56000000
Time:2015-05-22T13:21:53.5205261Z At
C:\Users\Samuel\Source\BaseDataInstall\BaseDataInstall\AzureHelpers.ps1:45
char:2
+ Invoke-RestMethod -Uri $uriString -Method $method -Headers $headers -Body $body
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebExc
eption
+ FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand
EDIT: Here's the Example output from the $headers variable outside the function...
Key : x-ms-version
Value : 2014-02-14
Key : x-ms-date
Value : Tue, 26 May 2015 19:30:20 GMT
Key : Authorization
Value : SharedKeyLite <MyStorageName>:lf+ndqhi4OeJhIfLljugT0dfcLbqXDBHwrQJn9Q66HQ=

Answer 1

So this ended up being a simple coding error :(
I feel kinda silly posting this now, but I'm going to post an answer cause I couldn't find a working Authorization builder for Azure in Powershell anywhere. This one does work for Azure tables...
function GenerateHeader($accountName, $accountKey, $action)
{
$xmsdate = get-date
$xmsdate = $xmsdate.ToUniversalTime()
$xmsdate = $xmsdate.toString('R')
$newLine = "`n";
$action = $action.ToLower()
$message = $xmsdate + $newline + "/" + $accountname + "/" + $action;
$hmacsha = New-Object System.Security.Cryptography.HMACSHA256
$hmacsha.key = [Convert]::FromBase64String($accountKey)
$signature = $hmacsha.ComputeHash([Text.Encoding]::UTF8.GetBytes($message))
$signature = [Convert]::ToBase64String($signature)
$headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$headers.Add("Content-Type", "application/json")
$headers.Add("x-ms-date", $xmsdate)
$headers.Add("Authorization", "SharedKeyLite " + $accountName + ":" + $signature)
return $headers
}

Answer 2

There seem to be a change in the Azure API. I had to disable the "toLower" statement for this to Work.
function GenerateHeader($accountName, $accountKey, $action)
{
$xmsdate = get-date
$xmsdate = $xmsdate.ToUniversalTime()
$xmsdate = $xmsdate.toString('R')
$newLine = "`n";
# $action = $action.ToLower()
$message = $xmsdate + $newline + "/" + $accountname + "/" + $action;
$hmacsha = New-Object System.Security.Cryptography.HMACSHA256
$hmacsha.key = [Convert]::FromBase64String($accountKey)
$signature = $hmacsha.ComputeHash([Text.Encoding]::UTF8.GetBytes ($message))
$signature = [Convert]::ToBase64String($signature)
$headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
# $headers.Add("Content-Type", "application/json")
$headers.Add("x-ms-date", $xmsdate)
$headers.Add("Authorization", "SharedKeyLite " + $accountName + ":" + $signature)
return $headers
}
I hope this helps someone :-)